Spring clamp connector



April 3 1951 E. s. HEBELER 2,547,080

SPRING CLAMP CONNECTOR Filed July 20, 1948 6%@ af MOR Patented Apr. 3,1951 UNITED STATES PATENT OFFICE SPRING CLAMP CONNECTOR Edward s.Hebeler, Williamsville, N. Y. Application July 20, 1948, Serial N0.39,699

6 Claims. (Cl. 173-269) This invention relates to improvements inconnections between electrical conducting cables of the type includingmany relatively small wires to provide ilexibility of the cable, and aconnector therefor.

Cables of the type made of numerous small diameter wires, in such amanner that they will be readily exible, are commonly used in connectionwith Welding and other apparatus in which the cable is flexed, twistedand bent during the use of the apparatus, and diculty has beenexperienced in the past in making a good connection between an end of acable of this type and a connector, unless the end of the cable issoldered to the connector., This, however, has been found objectionable,for the reason that the solder tends to run along the cable and torender that part of the cable in which the wires are connected by solderstii. Consequently, at the end of the solder, the thin wires will bendto a greater extent than at those parts of the cable which are free fromsolder, thus causing rapid breaking of the wires at the ends of thesoldered parts of the cable, because the small wires will be subjectedto the maximum bending at the portion thereof adjacent to the portion ofthe cable rendered rigid by the solder.

Unsoldered cable ends are very difficult to hold in clamped tight andrigid electrical connection with a connector by means of the usualclamping screws or bolts, since even if such screws or bolts areinitially tight and form a good electrical connection, it has been foundthat such connections become loosened during the use of the connection,so that eventually there is not sufficient pressure between the cableand the connector. This re duction in pressure results in a poorelectrical connection and in heating of the connector and the cable endand the heating in turn results in forming an oxide on the surface ofthe wires or connector which in turn further increases the resistance ofthe connection and results in further heating of the same, so thateventually the connection becomes excessively hot and fails to transmitthe required amount of current from the cable to the connector. In somecases, the connector becomes too hot to be handled and may constitute are hazard.

I have found that the reason for this rapid heating of the connectionbetween the cable and the connector is due to the shifting of Wires ofthe cable at the point or points where the pressure is applied, due tothe fact that the connector, when used in connection with welding orother operations is moved, turned and twisted. This shifting of theWires of the cable gradually reduces the pressure urging the cable intocontact with the terminal, so that even if a very good electricalconnection is originally made by clamping the screws or bolts uptightly, yet as the wires Y 2 of the cable shift relatively to eachother, this pressure gradually decreases, thus resulting ina graduallyincreasing resistance and consequent heating of the connection.

One of the objects of this invention is to provide an electricalconnection between a cable end and a connector by means of which aconstant pressure is exerted on the cable, pressing the same toward theconnector, which pressure is maintained in spite of the shifting of thewires of the cable.

A further object of this invention is to provide a connection of thistype in which a spring is employed which exerts a substantially constantpressure urging the cable into contact with the connector at all times,regardless of the shifting of the wires of the cable relatively to eachother. A further object of this invention is to provide a connectionbetween a cable and connector which also serves to prevent the pullingof the cable out of the connector. A further object is to provide aconnection which is so constructed that any pulling of the cablerelatively to the connector in a direction to disengage the same fromthe connector will result in increased tension and gripping of the cableto the connector.

Other objects and advantages of this invention will vappear from thefollowing description and claims.

In the accompanying drawings, which illustrate by way of example certainembodiments of this invention:

Fig. 1 is a side elevation of a holder for a welding rod to which acable connection embodying this invention may be applied.

Fig. 2 is a fragmentary, longitudinal, central, sectional view thereof.

Fig. 3 is a transverse section thereof, on line 3-3, Fig. 2.

Fig. 4 is a fragmentary, top plan view thereof.

Fig. 5 is a fragmentary, longitudinal, central sectional elevation of aconnection of modified construction.

Fig. 6 is a transverse sectional view thereof, on line 6 6, Fig. 5. Y

Fig. '7 is a perspective view of a spring which may be employed to forma connection between the cable and the connector.

Fig. 8 is a fragmentary, longitudinal, central, sectional elevation of aconnection of another modified form.

Fig. 9 is a transverse sectional elevation thereof, on line 9 9, Fig. 8.

Fig. 10 is a transverse sectional view of a connector showing aconnection of modiiied construction.

Fig. 11 is a perspective view of the combined spring and pressure padshown in Fig. 10, on an ,enlarged scale.

I have in Fig. 1 illustrated a holder for a Weld-= ing rod to which aflexible cable may be connected by means of connections embodying myinvention. It will be understood, however, that it is not intendedthereby to limit this invention for use with welding rod. holders, sinceit will be obvious that the improvements embodying this invention may beapplicable to any connection between a flexible cable and a rigidconnector therefor.

In Fig. 1, the welding rod holder includes: a pair of gripping members Iand II which are pivotally connected, for example, by means' of a pivotI2. The gripping member II has a handle I4 arranged thereon by means ofwhich the pivoted gripping member II. may be swung about thepivot I2 toenable a welding rod I5 to be gripped in any of the, notches or recessesI6 in the jaws of the gripping member. The rod' is securely held in thejaws by means of a compression spring I'Iy acting on the two grippingmembers Il! and II in a direction to close the jaws.

The rod gripping member I0 is provided'. at the rear thereof with aconnector, indicated in general by the reference character I8, forconnection with a flexible cable,I9. A sleeve 20 of insulating materialis usually slid over the connector' so that, the operator, in using thedevice, grips the insulating handle portion Ill and the sleeve 2S toavoid contact with current-carrying metal parts of the device.

The connector I8 may be of any usual or suitable construction, and inthe form illustrated by Way of example, it, is of. substantially hollow,cylindrical or tubular form, the interior of the cylindrical portionhaving a substantially cylindrical aperture 22 of sufficient size toreceive the bare wire portion 24 of the cable. A part of the cylindricalportion of the connector intermediate of the ends thereof is omitted orremoved', thus forming a trough-shaped portion 25` and a cylindricalportion 26 at thel end of the connector, through which the Wire portionof an end of the cable may be passed to lie in the trough-shaped portion25. In these connectors as heretofore constructed' suitable clampingmeans including screws, bolts or the like were employed for pressingthe. wire portion of the cable into the lower or trough-shaped portion25. of the cylindrical part of the connector.

In the use of an implement such as an electrode or rod holder of awelding apparatus, the connection between the cable I9 and the connectorI8 is subject to substantially continuous movement of the connector I8during the time that the operator uses the welding rod holder. Thewelding operation requires bending, twisting, turning and othermovements of the welding rod holder, and all of these movements aretransmitted to the. end of the cable which is connected with theconnector. It is, therefore, necessary that these cables have a highdegree of flexibility and, consequently, they are made of a large numberof fine or small gage current-conducting wires. Usually the connectionbetween the cable and the connector includes screws or bolts which aretightened to apply pressure to the, cable for at- 'caching the same tothe connector and, as heretofore stated, the repeated movements of therod holder results in the fine Wires of the cable shifting andreadjusting themselves at the point or points at which the clampingpressure is applied, so that the pressure acting on the cable'isgradually reduced due to lateral slipping of the wires of the'cable,thereby producing a poor connection between the cable and connector,which results in the heating of the connector and adjacent parts of thecable, which in turn results in the covering of. the. wires andconnector with a nlm of oxide which makes the. electrical connectionworse.

In order to overcome the difficulties heretofore experienced withclamping devices for securing the cables to connectors, I have foundthat the heating of the cables and the connectors can be greatly reducedby providing a yielding or spring memberv for exerting a resilient forceagainst a portion of the cable within the connector. By means of thisconstruction, if the wires of the cable, during the continued use ormoving of the connector, become shifted or readjust themselves, thisshifting or readjusting will be followed with a corresponding movementof' the yielding or spring member, so that substantially the same forcewill be exerted on the cable as was exerted on it before the shifting oradjusting of the wires of the cable took place.

In order to accomplish this result, I have provided in Figs. 2 to 4, aleaf spring 3G which is curved to follow approximately the contour ofthe outer surface of the cylindrical portion of the connector and whichhas a plurality of spring arms 3S extending therefrom over thetroughshaped part 25 of the connector, two such arms being shown in theconstruction illustrated. The outer ends of the arms have a portion 32bent toward the axis of the connector I8, and a pressure pad orintermediate pressure transmitting member 33 is arranged between thebare portion 2li of the cable and the downwardly extending portions 32of the arms of the spring. This intermediate member may be providedwitha lower surface formed to contact with the wires of the cable and agroove 35 in the upper surface in which the extensions 3l of the armsAmay seat. This spring member may be sprung around the trough portion ofthe connector, whereupon the arms 3l will exert a force against the pador intermediate member 33, urging the same against the wires of thecable to press the same into the trough-shaped part 25'. By means ofthis con'- struction, the shifting of the wires of the cable relativelyto each other Will not result in any material reduction of pressure onthe cable, since if the wires of the cable become more compacted orspread laterally under theintermediate member 33,v this member will beurged farther into the trough of the connector by means of the springpressure of the arms 3l. j

One end of the intermediate member 33' may extend under the cylindricalportion 26 ofthe connector,r and this cylindrical portion also serves asa stop against which one of the arms SVI Vof the spring member may` bearto resist pulling of the cable out of the connector. The pad orintermediate member may also be of slightly tapering or wedge-shapedform with the end thereof of least height extending into thecylindricall portion 2t. Consequently, any pulling on the cable 24 willcause the wedge-shaped intermediate member 33 to enter farther into thecylindrical part 2S, thus causing this member to press more tightlyagainst the cable, and thus form an improved electrical connection,supplementing the action of' the spring 30 and also gripping the cablemore securely in the conjnector to resist removal of the same lengthwisetherefrom. The wedging ofv the intermediate member 33 into thecylindrical part 26 exerts pressure against the part of the cableadjacent trough portion 25 of the connector.

mediate member 45. 'connector below the trough 25 may be provided to thesmaller end of the wedge-shaped interl'mediate member 33 and the springarms 3| serve to apply adequate pressure to the other end of theintermediate member 33 to assure a good electrical connection betweenthe cable and the connection throughout the length of the wedgeshapedintermediate member 33. The wedging action of the cylindrical partsupplements the pressure applied to the cable, but the spring arms 3|alone are capable of pressing the cable against the connector withsufficient force *to ensure a good electrical connection.

A In the modified construction shown in Figs. 5 fto 7, the connector issimilar to the one shown lin Figs. 1 to 4, except that the annular orcylin- Idrical end portion 3S is provided on the upper portion of itsinner surface with a tapered or inclined face 31. A pressure pad orinterme-A 'diate member 45 of somewhat different construction isemployed, that shown having at one vend thereof a wedge-shaped portion4| adapted to cooperate with the inner tapered surface 31 'of thecylindrical part 35. The pressure pad or intermediate part 45 is urgedinto engagement with the wire portion 24 of the cable by means `hof awire spring member having a U-shaped portion 43 which engages theunderface of the The ends of the legs of the U-shaped member are curved:upwardly as shown at 44 and terminate in down- 51' wardly extending endportions 45 which are Aadapted to enter into grooves or recesses formedin vthe upper face of the pressure pad or inter- The outer surface ofthe with a series of notches 41 into which the legs of the U-shapedportion 43 may enter to hold this part of the spring against movementlengthwise of the connector I8.

',In'applying this spring to the pressure pad or intermediate member 45,this member is first forced to the right in Fig. 5, so that the wedgepart 4| will be forced into the cylindrical part '36 of the connection,and the spring may then be applied to the pad or intermediate member 4Uby inserting the ends 45 into the grooves or 'recesses in the upper faceof the pad. The lowker U-shaped part 43 of the spring is then moved tothe right in Fig. 5 as far as possible and en tered into two of thenotches 41, so that the curved parts 44 of the spring' member willassume inclined positions, as shown by broken lines in Fig. 5. lThisspring will, consequently, serve the two-fold purpose of pressing thepressure pad or intermediate member 4G directly against the wire part ofthe cable to force the same into lthe trough 25, and the upper ends ofthe curved parts 44 of the spring will also have a tendency to assumevertical positions. Since the notches 41 prevent the lower U-shaped partof the spring from moving to the left in Fig. 5, it will be obvifousthat the spring will, consequently, tend to urge the pad or intermediatemember 45 to the right to retain the same in wedging relation to I.thecylindrical part 36.

In this construction, as well as that described in connection with Figs.2 to 4, the spring member will provide a continuous force on the pres--sure pad 'so that if the wires of the cable be- 'comeireadjusted orshifted laterally to occupy a smaller space vertically, the pad, becauseof the pressure oi` the spring, will follow up the wire part of thecable so that substantially the same ypressure will be applied theretoafter reconnector 53.

adjustment of the wires ofthe cable asbefore the re-adjustment tookplace. :z

Figs. 8 and 9 show still another modified form of my invention, in whicha connector also has a cylindrical portion 5| arranged between the endof the connector and the cutout portion of the same, and thiscylindrical portion is provided with a tapered inner surface 52 similarto the surface 31 shown in Fig. 5. The wire portion 24 of the cable i9is pressed into the trough 25 of the connector by means of a pressurepad or intermediate member 53. In this construction, the pressure pad orintermediate member 53 is pressedl into wedging relation with thecylindrical part 5| and into engagement with thewire part 24 of thecable by means of. a coil spring 55, one end of which enters a seaty orrecess -56 formed on the pressure pad 53, the other end of which isseated in a recess 51 formedin the The upper face of the pressure memberhas the upper surface 55 thereof curved downwardly lengthwise thereof,which causes the coil spring 55 to assume a curved position when theends thereof are arranged in the seats 56 and 51. This upper surface isalso trough-shaped to receive the intermediate portion of the spring 55.Consequently, the coil spring 55 exerts pressure lengthwise of theconnector against the part of the pressure pad which is formed to bewedged into the inclined inner surface of the cylindrical part 5| of theconnector. This pressure exerted by the coil spring also tends to causethe coil spring to .become bowed and thus exerta pressure against theupper face of the pressure pad or intermediate member, thus urging thesame toward the wire part of the cable to press the same into the trough25 of the connector. In this construction, it will also be obvious thatreadjustment of the wires of the cable relatively to each other will befollowed by a movement' of the pressure pad toward the cable, due to theaction of the spring 55, so that a loose connection between the wireportion of the cable and the connector is prevented. By urging thepressure a pad or intermediate member into wedging relation with thecylindrical part 5|, the spring further assures compression of the wirepart of the cable adjacent to the cylindrical part 5| against the troughof the connector 5|). In the construction shown in Figs. 5 to 9, it willnoted that the springs shown exert both transverse pressure on theintermediate member to 'force the cable into the trough of theconnector, and lengthwise pressure against the intermediate member toproduce a Wedging action of the cable against the connector. y

In the construction shown in Fig. l0, the connector shown is the same inconstruction as the oneshown in Figs. 1 to 4, including a troughshapedportion -25 and a cylindrical end portion 26. In this construction, thespring and the pressure pad or intermediate member are formed in onepiece. The spring is in the form of a band or strip of spring metalhaving aA part 55 formed to extend partly around the outer surface ofthe trough portion 25 and a part 65 which extends over the open face ofthe trough portion. This latter part terminates in a part 51 whichconstitutes a pressure pad or intermediate member which is formed toengage the wire portion 24 of the cable and to press the same into thetrough 25. This pressure pad portion 51 and the adjacent portions of thespring part 66 are preferably provided with a plurality of slits 68which divide this part of the spring into aA plurality of fingers, eachof which may engage a part of the cable independently of the otherfingers. Preferably the ends of the fingers which formv the pressure padare slightly inclined in such manner thatk the lower edge portions '[8thereof grip they cable. In securing this spring on a connector, thehigher edges 'H of the lingers of' the pad are arranged adjacent to thecylindrical. portion 26., so that if a pull is exerted on the. cable topull the same from the connector, the lower edges of the pressure padlingers will tend tob-ite into the cable and oppose such pull, and thespring itself will abut against the cylindrical portion 25 and will beheld on the connector thereby.

It will be understood that various changes in the. details, materials,and arrangements oi parts which have been herein described andillustrated in; order to explain the nature of the invention. maybe madeby those skilled in the art within the principle and scope of theinvention, as expressed in the appended claims.

I claim as my invention:

1. An electrical connection for a flexible current-carrying cablecomprising a large number` of small wires, including a rigid connectorhaving a hollow cylindrical portion at one end thereof through which thecable may extend and a trough-shaped portion adjacent thereto into whicha part of said cable maybe laid lengthwise, an intermediatepressure-transmitting member overlying said trough-shaped part of saidconnector and having an end` portion thereof formed to extend into saidcylindrical portion and to cooperate therewith to wedge saidintermediate member against said cable, and a spring acting on saidintermeditae member to force the same against the portion of the cablelying said trough-shaped part.

2. An electrical connection for a ilexible current-carrying cablecomprising a large number of small wires, including a rigid connectorhavi-ng a trough-shaped part into which a part 0i said cable may be laidlengthwise, and a hollow cylindrical portion through which an end of acable extends before entering said trough-shaped part, an intermediatepressure-transmitting member overlying said trough-shaped part of saidconnector and entering said hollow cylindrical portion of' saidconnector, and a resilient member acting on said intermediate member tourge the same against the cable to force the cable into said trough,said cylindrical member forming a stop which said resilient member mayengage to resistv pulling said cable out of said connector.

- 3.. An electrical connection for a flexible current-carrying cablecomprising a large number of small wires, including a rigid connectorhaving ahollow cylindrical portion at one end thereof through which thecable may extend and a trough-shaped portion adjacent thereto into whicha part of said cable may be laid. lengthwise an intermediatepressure-transmitting member overlying said trough-shaped part of saidconnector and having an end portion. thereof formed to extend into saidcylindrical portion and to. cooperate therewith to. wedge saidintermediate member against said cable, and a spring acting on saidintermediate member to force the same .against the portion of the cablelying in said trough-shaped part, said spring. also exerting pressure onsaid intermediate member to. urge the same in` the direction of itsylength into wedging relation to said cylindrical portion of saidconnector.

4. An electrical connection for a. exible current-carrying cablecomprising a large. number of small wires, including a rigid connectorhaving a substantially cylindrical part at an end thereof and atrough-shaped part adjacent to said cylindrical part into which a partof said cable may be laid lengthwise alter passingl through said hollowcylindrical part, an intermediate member having one end thereofwedge-shaped and formed to enter said cylindrical part to wedge saidcable therein, and ay coil compression spring having one end thereofengaging said connector and the other end engaging said intermediate.ymember to force. thel same into wedging engagement with said cylindricalpart and said connector, said coil spring being bowed to engage` anotherportion of said intermediate member to yield- -ingly urge the sametoward said trough to compress said cable between said intermediatemember and. said trough.

5. An electrical connection for a iiexible. current-carrying cablecomprising a large number of small wires, including a rigid connectorhaving a trough-shaped part into which a. part of said cable may belaid` lengthwise, and a hollow cylindrical portion through which an endof a cable extends before entering. said trough-shaped part, a yieldingmember exerting pressure on said cable in a direction to press. the sameinto said trough, an intermediate member interposed between said cableand said yielding member 'and having a tapering end portion extendinginto said cylindrical portion of said connector and serving to wedgesaid cable and intermediate member into L* said cylindrical portion whensaid cable is subjected to a pull in a direction to withdraw the endthereof from said connector.

6. An electrical connection for a flexible current-carrying cablecomprising a large number of small wires, including a rigid connectorhaying a trough-shaped part into which a part of said cable may be laidlengthwise, a spring member extending partly around said connector andhaving a plurality of arms extending above said trough, and anintermediate member interposed between said spring arms and said cable,said spring arms acting on said intermediate member to press the sameagainst said cable.

EDWARD S. HEBELEE.

REFERENCES CITED lThe following references are of record inthe file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,099,034 Girard Jan. 2, 191.41,551,252 Johnson, Jr. Aug., 25, 1925 1,552,244 Thomas Sept. 1, 19251,860,262 Niemann May 24, 1932 2,198,193 Drachman et al. Apr.. 23, 1940FOREIGN PATENTS Number Country Date 485,888 France. Feb. 15,1918 886,954France Oct. 29, 1943

